First seen on the Green Chair Press blog, Book Traces is a project to track down and digitize the human markings in 19th-century books.
"Thousands of old library books bear fascinating traces of the past. Readers wrote in their books, and left notes, pictures, letters, flowers, locks of hair, and other things between their pages. We need your help identifying them because many are in danger of being discarded as libraries go digital. Books printed between 1820 and 1923 are at particular risk. Help us prove the value of maintaining rich print collections in our libraries."